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Статті в журналах з теми "MoS2 Nanoparticles"
1
Chikukwa, Evernice, Edson Meyer, Johannes Mbese, and Nyengerai Zingwe. "Colloidal Synthesis and Characterization of Molybdenum Chalcogenide Quantum Dots Using a Two-Source Precursor Pathway for Photovoltaic Applications." Molecules 26, no. 14 (July 9, 2021): 4191. http://dx.doi.org/10.3390/molecules26144191.
Повний текст джерелаАнотація:
The drawbacks of utilizing nonrenewable energy have quickened innovative work on practical sustainable power sources (photovoltaics) because of their provision of a better-preserved decent environment which is free from natural contamination and commotion. Herein, the synthesis, characterization, and application of Mo chalcogenide nanoparticles (NP) as alternative sources in the absorber layer of QDSSCs is discussed. The successful synthesis of the NP was confirmed as the results from the diffractive peaks obtained from XRD which were positive and agreed in comparison with the standard. The diffractive peaks were shown in the planes (100), (002), (100), and (105) for the MoS2 nanoparticles; (002), (100), (103), and (110) for the MoSe2 nanoparticles; and (0002), (0004), (103), as well as (0006) for the MoTe2 nanoparticles. MoSe2 presented the smallest size of the nanoparticles, followed by MoTe2 and, lastly, by MoS2. These results agreed with the results obtained using SEM analysis. For the optical properties of the nanoparticles, UV–Vis and PL were used. The shift of the peaks from the red shift (600 nm) to the blue shift (270–275 nm and 287–289 nm (UV–Vis)) confirmed that the nanoparticles were quantum-confined. The application of the MoX2 NPs in QDSSCs was performed, with MoSe2 presenting the greatest PCE of 7.86%, followed by MoTe2 (6.93%) and, lastly, by MoS2, with the PCE of 6.05%.
2
Mandal, Soumen, Rajulapati Vinod Kumar, and Nagahanumaiah. "Silver and molybdenum disulfide nanoparticles synthesized in situ in dimethylformamide as dielectric for micro-electro discharge machining." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 5 (September 30, 2017): 1594–99. http://dx.doi.org/10.1177/0954405417733019.
Повний текст джерелаАнотація:
The research focuses on the applicability of silver (Ag) and molybdenum disulfide (MOS2) nanoparticle synthesized in situ in dimethylformamide solution as dielectric material for micro-electro discharge machining. Ag nanoparticles (~120 nm size) and MOS2 nanoparticles (~20 nm size) were synthesized in dimethylformamide solution using a combination of nanoparticle solution synthesis routes. A setup for micro-electro discharge machining was developed in-house with an arrangement to generate spark at varying voltages. The setup was integrated with a precise linear height gauge to measure the spark gap during the experiments where Ag and MOS2 nanoparticles in dimethylformamide solution served as dielectric. The debris was collected and was characterized for each of the experiments. The feature size of the crater generated during the micro-electro discharge machining was also studied. The experiments were repeated with silver and MOS2 nanoparticle powder mixed with dimethylformamide as dielectric. It was observed that in situ prepared nanoparticles in dimethylformamide offered much better machining performance in terms of process stability, crater size and material removal rates. On use of in situ synthesized nanoparticle dielectric, the material removal rate increased by nearly two to three times whereas the spark gap increased by about two times.
3
Hu, J. J., J. H. Sanders, and J. S. Zabinski. "Synthesis and microstructural characterization of inorganic fullerene-like MoS2 and graphite-MoS2 hybrid nanoparticles." Journal of Materials Research 21, no. 4 (April 1, 2006): 1033–40. http://dx.doi.org/10.1557/jmr.2006.0118.
Повний текст джерелаАнотація:
The structures of inorganic fullerene-like (IF) MoS2 nanoparticles produced by arc discharge in water are reported in this paper. To adjust the chemistry and structure of IF nanoparticles, 2H–MoS2, graphite and composite 2H–MoS2/graphite rods were used as electrodes in the arc synthesis. In comparison to using MoS2 as both anode and cathode, mixed electrodes (graphite and MoS2) significantly increased the discharge current. Various IF-MoS2 nanoparticles were successfully produced by the water-based arc method, and their microstructures were studied using a transmission electron microscope equipped with an x-ray energy dispersive spectrometer. The IF–MoS2 nanoparticles commonly had a solid core wrapped with a few MoS2 layers and exhibit some differences in size and geometry. The IF-MoS2 nanoparticles were typically 5–30 nm in diameter as observed by transmission electron microscopy. Tiny IF-MoS2 nanoparticles (<10 nm) along with fragments of lamellar MoS2 were produced from arc discharge in water using both graphite and MoS2 electrodes. Carbon nano-onions and hybrid nanoparticles consisting of carbon and MoS2 were synthesized by using mixed electrodes of graphite and 2H–MoS2. The hybrid nanoparticles were MoS2 cores covered by a graphite shell. Our results show that the water-based arc method provides a simple tool for producing a variety of nanoparticles including some familiar and some new hybrid structures.
4
Liu, Xianglin, Yongsong Ma, Peng Li, Huayi Yin, and Dihua Wang. "Preparation of MoB2 Nanoparticles by Electrolysis of MoS2/B Mixture in Molten NaCl-KCl at 700 °C." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 123509. http://dx.doi.org/10.1149/1945-7111/ac41f4.
Повний текст джерелаАнотація:
MoB2 is synthesized by the electrochemical reduction of solid MoS2/B mixture in molten NaCl-KCl at 700 °C. Unlike the traditional methods, the electrolysis method employs the low-cost MoS2 feedstock and the boronization reaction happens at a low temperature of 700 °C. The electrochemically induced boronization involves two steps: the electrochemical desulfurization to generate Mo and the reaction of Mo with B to form MoB2. The S2− released from the reduction of MoS2 transfers to the carbon anode and is oxidized to sulfur gas, realizing a green synthetic process. In addition, the influences of molar ratio of MoS2 and amorphous boron and electrolysis cell voltage on the phase composition and morphology of electrolytic products were studied. The obtained MoB2 particles possess a uniform nodular morphology. Overall, this paper provides a straightforward and green process to prepare MoB2 nanoparticles using economically affordable raw materials at low temperature, and this method can be extended to prepare other borides.
5
Hu, Kun Hong, Xian Guo Hu, Xiao Jun Sun, He Feng Jing, and Song Zhan. "Synthesis and Characterization of Nanosize Molybdenum Disulfide Particles by Quick Homogeneous Precipitation Method." Key Engineering Materials 353-358 (September 2007): 2107–10. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2107.
Повний текст джерелаАнотація:
Molybdenum sulfide nanoparticles were prepared via quick homogeneous precipitation method (QHPM) by the reaction between Na2MoO4 and CH3CSNH2 in the presence of sulfuric acid at 80 oC. The as-synthesized molybdenum sulfide particles were studied by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The results showed that the as-synthesized molybdenum sulfide was amorphous MoS3 nanoparticles with an average size of 40 nm. The resultant amorphous MoS3 nanoparticles were then calcined under hydrogen gas flow at a selected temperature for 50 minutes. The results of XRD, TEM, and HRTEM confirmed that the MoS2 nanoparticles with about 40 nm were prepared from the amorphous MoS3 nanoparticles at 780 oC.
6
Ilie, Filip, and Andreea-Catalina Cristescu. "A Study on the Tribological Behavior of Molybdenum Disulfide Particles as Additives." Coatings 12, no. 9 (August 25, 2022): 1244. http://dx.doi.org/10.3390/coatings12091244.
Повний текст джерелаАнотація:
Molybdenum disulfide (MoS2) is used as a solid lubricant and is well known for its tribological behavior (friction and wear). The tribological properties of the lubricating oil–MoS2 nanoparticles mixture in different conditions of friction are studied using a four-ball tribometer, and the operating conditions of the four balls when immersed can be modeled. The current paper presents a calculating method for the critical sliding velocity (ωcr) and friction maximum torque (Mfmax) depending on the temperature (T) from the contact areas, obviously demonstrating low tribological performances. The film composition formed by friction, the topography, and the morphology of the particles and the friction-and-wear tracks of the balls following experiments using contact surfaces are analyzed and investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscope (TEM). XPS and SEM show that nanoparticles by deposition form a protective and lubricating layer of MoS3, which allows for an increase in the friction pair’s load capacity. MoS2 nanoparticles (n- MoS2 of ~ 40 nm in diameter) compared to the common (commercial) MoS2 particles (c-MoS2 of ~ 1.5 μm in diameter) presented lower friction coefficients and higher wear-resistance values, due to the protective-layer microstructure as an intermediate lubricant between the contact surfaces. Therefore, the present paper reports the tribological properties of the lubricating oil with n-MoS2 as an additive compared to the c-MoS2, and by the application of the friction modeling theory using a Couette flow, it was possible to calculate the temperature, T, when the friction torque, Mf, was at its maximum, the basis on which the value of its sliding velocity, ω, was obtained corresponding to the contact areas of the four-ball system.
7
Gao, Bin, and Xiao Jun Zhang. "Synthesis of MoS2 Nanoparticles with Inorganic Fullerene-Like Structure from Molybdenum Trioxide and Sulfur." Advanced Materials Research 554-556 (July 2012): 601–4. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.601.
Повний текст джерелаАнотація:
MoS2 nanoparticles with fullerene-like (IF-MoS2) structure were successfully obtained at heating temperature higher than 840 °C by chemical vapor deposition method in a three-tube furnace using MoO3 and S (sulfur) powders as raw materials. The synthesized samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and energy dispersion X-ray spectrometerrespectively. IF-MoS2 nanoparticles can be obtained only in the narrow temperature range of 840 °C-870 °C, and the diameter of IF-MoS2 nanoparticles increases with temperature. A gradual formation mechanism of IF-MoS2 nanoparticles was discussed in detail.
8
Shi, Shih-Chen, and Shia-Seng Pek. "Third-Body and Dissipation Energy in Green Tribology Film." Applied Sciences 9, no. 18 (September 10, 2019): 3787. http://dx.doi.org/10.3390/app9183787.
Повний текст джерелаАнотація:
Green tribology film comprising hydroxypropyl methylcellulose modified with nanoparticles and molybdenum disulfide was prepared by the solvent evaporation method. The nanoparticle additives were Al, Cu, Al2O3, and CuO. The tribological behavior of nanoparticles and MoS2 was investigated using a ball-on-disk tribometer. The surface morphologies and worn surfaces were observed through scanning electron microscopy. The preferred orientation and crystallographic structure of MoS2 and nanoparticles in the composites were studied via X-ray diffraction. Energy-dispersive X-ray spectroscopy was used to analyze the transfer film formed on the counterball. The surface profile, wear depth, wear width, and wear volume were studied by a 3D optical profiler. The synergistic effect of micro-platelet MoS2 and nanoparticles contributed to the excellent wear resistances. It was found that the wear volume of hydroxypropyl methylcellulose (HPMC)/MoS2 composites decreased dramatically when Al, Cu, and CuO were used as fillers, and it decreased slightly with Al2O3. The optimal wear resistance was obtained with 3 wt.% additives. These filled composites had a lower coefficient of friction lower than that of unfilled HPMC/MoS2. The optimal result was observed for the HPMC/MoS2/CuO 3 wt.% composite coating, which reduces the wear and friction coefficient by 90% and 84%, respectively, as compared to coatings without additives. Nanoparticles existed in the wear track as the third particles improved the load capacity of the composites. The wear mechanism of the composites is discussed in terms of the worn surfaces and the analysis of transfer film with a third-body approach. The dissipation energy theory is used to evaluate the dominant wear mechanism of the system.
9
Guo, Jianjun, Bo Yang, Qiang Ma, Sandra Senyo Fometu, and Guohua Wu. "Photothermal Regenerated Fibers with Enhanced Toughness: Silk Fibroin/MoS2 Nanoparticles." Polymers 13, no. 22 (November 15, 2021): 3937. http://dx.doi.org/10.3390/polym13223937.
Повний текст джерелаАнотація:
The distinctive mechanical and photothermal properties of Molybdenum sulfide (MoS2) have the potential for improving the functionality and utilization of silk products in various sectors. This paper reports on the preparation of regenerated silk fibroin/molybdenum disulfide (RSF/MoS2) nanoparticles hybrid fiber with different MoS2 nanoparticles contents by wet spinning. The simulated sunlight test indicated that the temperature of 2 wt% RSF/MoS2 nanoparticles hybrid fibers could rise from 20.0 °C to 81.0 °C in 1 min and 98.6 °C in 10 min, exhibiting good thermal stability. It was also demonstrated that fabrics made by manual blending portrayed excellent photothermal properties. The addition of MoS2 nanoparticles could improve the toughness of hybrid fibers, which may be since the mixing of MoS2 nanoparticles hindered the self-assembly of β-sheets in RSF solution in a concentration-dependent manner because RSF/MoS2 nanoparticles hybrid fibers showed a lower β-sheet content, crystallinity, and smaller crystallite size. This study describes a new way of producing high toughness and photothermal properties fibers for multifunctional fibers’ applications.
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Lee, G. H., J. W. Jeong, S. H. Huh, S. H. Kim, B. J. Choi, and Y. W. Kim. "A Simple Synthetic Route to MoS2 and WS2 Nanoparticles and Thin Films." International Journal of Modern Physics B 17, no. 08n09 (April 10, 2003): 1134–40. http://dx.doi.org/10.1142/s0217979203018636.
Повний текст джерелаАнотація:
We produced both MoS2 and WS2 nanoparticles by thermally decomposing M(CO)6 (M = Mo, W) in excess of H2S by using a hot filament. Both highly pure crystalline MoS2 and WS2 nanoparticles were efficiently produced over the filament temperature range from 300 to 800 °C. Particle diameter ranged from 2.0 to 5.0 nm and from 3.0 to 6.0 nm for MoS2 and WS2 nanoparticles, respectively. Fullerene-like particles such as nanotubes, onions, and empty and nested hollows were not produced. Both MoS2 and WS2 nanoparticles have a hexagonal close packed structure. Cell constants are determined to be a = 3.09 and c = 12.61 Å and a = 3.09 and c = 12.47 Å for MoS2 and WS2 nanoparticles, respectively, which are all consistent with the corresponding bulk values. Thin films of MoS2 and WS2 were also prepared by chemical vapor deposition of MoS2 and WS2 on stainless steel disks at 600-650 °C and low friction coefficients were obtained at an ambient atmosphere for both MoS2 and WS2 thin films, implying that they can serve as good solid lubricants.
Дисертації з теми "MoS2 Nanoparticles"
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Spence, D'Anne Emmett. "Intercalated MoS2 nanoparticles for enhanced dispersion in smokes and obscurants." College Park, Md. : University of Maryland, 2003. http://hdl.handle.net/1903/56.
Повний текст джерелаАнотація:
Thesis (M.S.)--University of Maryland, College Park, 2003.Thesis research directed by: Dept. of Chemistry and Biochemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
2
James, Derak J. "Synthesis and photocatalytic activity of the MoS2 and WS2 nanoparticles in degradation of organic compounds." CardinalScholar 1.0, 2009. http://liblink.bsu.edu/uhtbin/catkey/1503981.
Повний текст джерелаАнотація:
Nanoparticles of MoS2 and WS2 were synthesized by decomposing the
appropriate metal hexacarbonyl in the presence of sulfur dissolved in decalin at 140°C.
A significant fraction of the nanoparticles was ≤ 15 nm in diameter as verified by
Transmission Electron Microscopy. The process was repeated in the presence of silica
and then titania to produce supported metal sulfides. The unsupported nanoparticles were
found to exhibit a size-dependent shift in their threshold UV-visible absorption due to
quantum confinement. Photocatalytic properties of each sulfide from synthesis in decalin
were explored by using each as a catalyst in the photodegradation of methylene blue by
visible light. These sulfides were also used to catalyze the photodegradation of acetone.
Unsupported MoS2 and WS2 nanoparticles catalyzed the photodegradation of
acetone under visible light of ≥ 400 nm wavelength. This is the first study reporting the
photocatalytic properties of the unsupported WS2 nanoparticles. Photodegradation of
methylene blue under ≥ 435 nm irradiation was detected using unsupported WS2 but not
unsupported MoS2, likely because activity was masked by the likely photobleaching of
the dye. When deposited on silica or titania, the nanosized MoS2 and WS2 could be
uniformly distributed in aqueous solutions to maximize the photocatalytic efficiency. Correcting the absorbance measurements for light scattering by solids proved to be beneficial for extracting kinetic information. Both silica deposited sulfides were found to significantly increase the rate of methylene blue photodegradation, and deposited WS2 increased this rate significantly more than deposited MoS2. Similarly, both titania deposited sulfides significantly increased the rate of methylene blue photodegradation, and the deposited WS2 increased this rate significantly more than the deposited MoS2Synthesis of the sulfide photocatalysts -- Characterization of synthesized nanoparticles -- Photocatalytic degradation tests : setup and protocols -- Photocatalytic degradation tests : results.
Department of Chemistry
3
Deshpande, Pushkar. "Interaction of MoDTC additive on TiO2 APS coating under mixed/ boundary lubrication conditions : A tribocatalytic process." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEC059/document.
Повний текст джерелаАнотація:
De nos jours, afin de réduire le frottement et l'usure dans les moteurs thermiques et par voie de conséquence les émissions polluantes ainsi que la consommation énergétique, des revêtements APS (Atmospheric Plasma Spray) sont appliqués sur les chemises des cylindres. Le MoDTC (Di-ThioCarbamate de Molybdène), est un additif organométallique largement utilisé dans la lubrification automobile pour réduire le frottement grâce à la formation sur les surfaces frottantes de feuillets de MoS2. Ce travail de thèse porte sur l’étude de la réaction tribochimique du MoDTC avec le revêtement TiO2 APS dans des conditions de lubrification mixte / limite. Des poudres de TiO2 de taille micrométrique ont été utilisées pour obtenir un revêtement APS de TiO2 de 70 µm d'épaisseur. Différents tribomètres ont été utilisés pour effectuer des essais de frottement en présence d’une huile de base contenant du MoDTC. Les résultats obtenus pour un contact acier / TiO2 APS lubrifié avec du MoDTC présente une réduction significative du frottement par rapport au contact acier / acier (contact de référence). Les analyses de surface montrent que le tribofilm formé sur le plan de TiO2 APS est composé de MoS2 et de MoO3 tandis qu’il est constitué d’oxysulfure de molybdène, de MoS2 et de MoO3 sur le plan de référence en acier. De plus, les résultats indiquent que des phases Magneli résistantes à l'usure sont formées sur la surface du plan de TiO2 réduisant ainsi l'usure du contact lorsque celui-ci est uniquement lubrifié avec l'huile de base. L'impact de divers paramètres tels que la rugosité, la température d'essai, la pression de contact, la concentration en MoDTC et le remplacement des billes en acier par des billes en céramique sur le comportement tribologique du TiO2 APS a également été étudié. Les résultats ont été comparés avec ceux obtenus dans les mêmes conditions avec un contact acier / acier de référence et révèlent que le coefficient de frottement est toujours plus faible dans le cas des contacts impliquant un revêtement de TiO2 APS. Des résultats similaires à ceux obtenus avec le TiO2 APS (en termes de comportement tribologique et de composition chimique du tribofilm) ont été obtenus avec des nanoparticules de TiO2 mélangées dans l’huile de base avec du MoDTC dans le cas d'un contact acier / acier de référence. Dans les deux cas, une décomposition complète de MoDTC conduisant à la formation de MoS2 a été observée. Un phénomène de tribocatalyse a été suggéré comme pouvant être le mécanisme responsable de la décomposition du MoDTC en présence de matériaux à base de TiO2 comme le revêtement TiO2 APS et les nanoparticules de TiO2Nowadays to reduce friction and wear as well as gas emission and oil consumption of the passenger car engines, Atmospheric Plasma Spray (APS) coatings are used on cylinder liner. MoDTC (Molybdenum Di-Thiocarbamate), organometallic friction modifier has been previously used to reduce friction by formation of layered molybdenum disulphide flakes. This study focuses on tribochemical interaction of MoDTC with TiO2 APS coating under mixed / boundary lubrication conditions. Fused and crushed micron sized powders were used to obtain a 70 µm thick TiO2 coating. Various tribometers were used to carry out tribotests in presence of lubricant containing MoDTC. Steel / TiO2 APS contact showed significant friction reduction than steel / reference steel contact. It was shown that the tribofilm is composed of MoS2 and MoO3 on TiO2 APS flats while it is composed of Mo-oxysulphide, MoS2 and MoO3 on reference steel flats. It was shown that wear resistant Magneli phases are formed on the surface of TiO2 APS disc, decreasing wear when the contact was lubricated only with base oil. Impact of various parameters like roughness, test temperature, contact pressure, concentration of MoDTC and change of counterpart materials from steel balls to ceramic balls, on the tribological behavior of TiO2 APS was also studied. Results obtained were compared with contacts involving reference steel and it was confirmed that friction coefficient was always lower in case of contacts involving TiO2 APS coating. Similar tribological results and chemistry were obtained for TiO2 nanoparticles blended with MoDTC in case of steel / reference steel contact. Both the cases, TiO2 APS and TiO2 nanoparticles showed complete decomposition of MoDTC to form MoS2. Tribocatalysis was suggested as the mechanism responsible for complete decomposition of MoDTC in case of TiO2 based materials like TiO2 APS coating and TiO2 nanoparticles
4
Wery, Madeleine. "Synthèse de catalyseurs de type coeur@coquille pour le procédé d’hydrodésulfuration en phase gazeuse." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF036.
Повний текст джерелаАнотація:
Afin de réduire la teneur en soufre des essences, l’hydrodésulfuration transforme les molécules soufrées en hydrocarbures en présence d’un catalyseur supporté (métaux de transition sulfurés : MoS2) et dopé (Co, Ni). Cette phase active, déposée sur des nanoparticules, présente un nombre plus important de défauts, sites actifs essentiels à la catalyse. Les nanoparticules ont un ratio S/V élevé, une grande réactivité de surface avec une juste utilisation des quantités de métaux. L’objectif de ce projet de thèse est de synthétiser des catalyseurs nanométriques de type coeur@coquille possédant une meilleure activité catalytique qu’un simple mélange mécanique de deux métaux sulfurés. Le coeur est composé de Fe3O4 ou de nanodiamants et la coquille de MoS2, NiMoS, CoMoS ou NiCoMoS, supporté sur du TiO2 ou de la γ-Al2O3. Une réaction modèle (HDS du thiophène) a été utilisée afin d’évaluer l’activité catalytique et d’optimiser la structure du catalyseur. L’étude portera sur les paramètres de synthèse et l’effet de la taille du coeur, la synthèse utilisée, les interactions entre le coeur et la coquille, le support, la (co)– promotion (Ni/Co) et l’activation par la températureIn hydrodesulfurization of fossil fuels, the sulfur levels are reduced by sulfur extraction from hydrocarbons by using supported catalysts (MoS2), doped (Co, Ni). Ultra-deep hydrodesulfurization will be achieved by improving new catalysts. Nanoparticles are a promising candidate with their high S/V ratio and permit to use the precise amount of metallic sulphide. The aim of this thesis is the synthesis of core@shell nanometric catalyst with improved activities. Core composed of Fe3O4 or nanodiamonds will be surrounded by a shell formed of MoS2, NiMoS, CoMoS or NiCoMoS, supported on TiO2, γ-Al2O3. Model reaction (thiophene) has allowed to compare conversion rates between each catalyst. Additionally, characterizations have provided a better understanding of the HDS catalyst structure and performances. Some factors have been investigated such as the size of the core, theinteractions between the core and the shell, the type of synthesis, the support chosen, the synergetic effect with doping ions and also the activation of the catalyst at low temperature
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Fraga, André Luis Silveira. "Nanoestruturas de Dissulfeto de Molibdênio : síntese e caracterização para produção de hidrogênio." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/180646.
Повний текст джерелаАнотація:
IV Resumo Título: Nanoestruturas de Dissulfeto de Molibdênio: Síntese e caracterização para produção de Hidrogênio Mestrando: André Luís Silveira Fraga Orientador: Prof. Marcos José Leite Santos Palavras Chave: nanoestruturas de MoS2, nanopartículas de ouro, semicondutores, produção de hidrogênio. Neste trabalho é apresentada a síntese e caracterização de nanoestruturas de MoS2 e nanoestruturas de MoS2 decoradas com nanopartículas de ouro. O MoS2 foi obtido através de rota hidrotermal a 200 °C durante períodos de síntese de 2, 6, 12 e 24 horas. Como precursores foram utilizados molibdato de sódio, ácido 3-mercaptopropiônico, cisteamina e L-cisteína. Para avaliar o efeito da presença dos ligantes nas estruturas, as amostras de MoS2 foram tratadas térmicamente a temperaturas de 250, 550 e 750 °C, em atmosfera de argônio. Com o objetivo de avaliar o efeito da presença de nanopartículas de ouro nas propriedades fotocatalíticas do material, foi realizada a síntese in situ de nanopartículas de ouro aderidas às estruturas de MoS2. Os materiais foram caracterizados através das técnicas de difração de raios X (DRX), microscopia eletrônica de transmissão (MET), microscopia eletrônica de varredura (MEV) e espectroscopia do ultravioleta e visível (UV-Vis). As áreas superficiais e quantidade de poros foram avaliadas através das técnicas de BET (Brunauer, Emmett and Teller) e DFT (density functional theory). O precursor ácido 3-mercaptopropiônico resultou na formação de aglomerados de nanofolhas com cerca de 500 nm de diâmetro na sua maior dimensão. Ao usar cisteamina e L-cisteína foram obtidas nanoestruturas com formato de nanoflores com cerca de 300 nm de diâmetro formadas por pétalas com cerca de 30 nm. Um resultado interessante foi a rápida formação das nanoflores na presença de L-cisteína. As estruturas de nanoflores apresentaram produção de hidrogênio de até 9,6 mmol/gh.In this work the synthesis and characterization of MoS2 nanostructures and MoS2 nanostructures decorated with gold nanoparticles is presented. The materials were obtained by hydrothermal route at 200 °C during synthesis periods of 2, 6, 12 and 24 hours. Sodium molybdate was used as Molybdenium precursor and 3-mercaptopropionic acid, cysteamine and L-cysteine as sulfur precursors. To evaluate the effect of ligands on the structures, the MoS2 samples were thermally treated at 250, 550 and 750 °C under argon atmosphere. The effect of gold nanoparticles on the photocatalytic properties of the material was evaluated by obtaining and materials with gold nanoparticle adhered to the MoS2 structures. The materials were characterized by X-ray diffraction (XRD) techniques, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and ultraviolet and visible spectroscopy (UV-Vis). The surface areas and amount of pores were evaluated using BET (Brunauer, Emmett and Teller) and DFT (density functional theory) techniques. The precursor 3-mercaptopropionic acid resulted in the formation of nano-foil agglomerates of about 500 nm in diameter. On the other hand, when using cysteamine and L-cysteine, flower-shaped nanostructures of about 300 nm in diameter formed by petals of about 30 nm were obtained. An interesting result was the rapid formation of nanoflores in the presence of L-cysteine. Nanoflower structures showed hydrogen production up to 9.6 mmol / gh.
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Rahneshin, Vahid. "Versatile High Performance Photomechanical Actuators Based on Two-dimensional Nanomaterials." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/549.
Повний текст джерелаАнотація:
The ability to convert photons into mechanical motion is of significant importance for many energy conversion and reconfigurable technologies. Establishing an optical-mechanical interface has been attempted since 1881; nevertheless, only few materials exist that can convert photons of different wavelengths into mechanical motion that is large enough for practical import. Recently, various nanomaterials including nanoparticles, nanowires, carbon nanotubes, and graphene have been used as photo-thermal agents in different polymer systems and triggered using near infrared (NIR) light for photo-thermal actuation. In general, most photomechanical actuators based on sp bonded carbon namely nanotube and graphene are triggered mainly using near infra-red light and they do not exhibit wavelength selectivity. Layered transition metal dichalcogenides (TMDs) provide intriguing opportunities to develop low cost, light and wavelength tunable stimuli responsive systems that are not possible with their conventional macroscopic counterparts. Compared to graphene, which is just a layer of carbon atoms and has no bandgap, TMDs are stacks of triple layers with transition metal layer between two chalcogen layers and they also possess an intrinsic bandgap. While the atoms within the layers are chemically bonded using covalent bonds, the triple layers can be mechanically/chemically exfoliated due to weak van der Waals bonding between the layers. Due to the large optical absorption in these materials, they are already being exploited for photocatalytic, photoluminescence, photo-transistors, and solar cell applications. The large breaking strength together with large band gap and strong light- matter interaction in these materials have resulted in plethora of investigation on electronic, optical and magnetic properties of such layered ultra-thin semiconductors. This dissertation will go in depth in the synthesis, characterization, development, and application of two- dimensional (2D) nanomaterials, with an emphasis on TMDs and molybdenum disulfide (MoS2), when used as photo-thermal agents in photoactuation technologies. It will present a new class of photo-thermal actuators based on TMDs and hyperelastic elastomers with large opto-mechanical energy conversion, and investigate the layer-dependent optoelectronics and light-matter interaction in these nanomaterials and nanocomposites. Different attributes of semiconductive nanoparticles will be studied through different applications, and the possibility of globally/locally engineering the bandgap of such nanomaterials, along with its consequent effect on optomechanical properties of photo thermal actuators will be investigated. Using liquid phase exfoliation in deionized water, inks based on 2D- materials will be developed, and inkjet printing of 2D materials will be utilized as an efficient method for fast fabrication of functional devices based on nanomaterials, such as paper-graphene-based photo actuators. The scalability, simplicity, biocompatibility, and fast fabrication characteristics of the inkjet printing of 2D materials along with its applicability to a variety of substrates such as plastics and papers can potentially be implemented to fabricate high-performance devices with countless applications in soft robotics, wearable technologies, flexible electronics and optoelectronics, bio- sensing, photovoltaics, artificial skins/muscles, transparent displays and photo-detectors.
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Bouet, Louis. "Valley dynamics and excitonic properties in monolayer transition metal dichalcogenides." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0033/document.
Повний текст джерелаАнотація:
La possibilité de créer des monocouches de dichalcogenures à métaux de transition (MoS2, WSe2,MoSe2 pour ceux étudiés dans ce manuscrit) a été démontrée récemment (2005) et a ouvert la voie à l’étude de ces matériaux sous leur forme 2D. Il apparaît depuis que les propriétés de ces semi-conducteurs sous leur forme monocouche offrent des perspectives intéressantes à la fois du point de vue de la physique fondamentale et des potentielles applications qui peuvent en découler ; en plus de bénéficier d’un fort couplage avec la lumière, l’existence d’un gap important (situé dans le visible, 1.7-1.8 eV) permet entre autres de réaliser des transistors d’épaisseur mono-atomique. Par ailleurs, la physique de ces matériaux est prometteuse pour les applications dans le domaine de l’optoélectronique. En effet, lorsque le matériau est affiné jusqu’à la monocouche atomique, son gap optique devient direct et la brisure de symétrie d’inversion associée au fort couplage spin-orbite provoque l’apparition de règles de sélection optique originales qui relient directement la polarisation de la lumière émise ou absorbée à une des deux vallées non-équivalentes de l’espace réciproque. Cela ouvre la possibilité d’explorer une nouvelle physique, basée sur l’indice de vallée et intitulée en conséquence vallée-tronique, avec comme perspectives futures la manipulation de l’indice de vallée et l’exploitation d’effetsliés à cette relation originale entre propriétés optiques et électroniques (effet vallée-Hall par exemple). Cemanuscrit de thèse regroupe une série d’expériences réalisées dans le but de comprendre et caractériser les propriétés optoélectroniques de ces matériaux. Un premier chapitre introductif présente le contexte scientifique de ces travaux de recherche et démontre l’origine des propriétés électroniques et optiques de ces matériaux via un modèle théorique simple. Le second chapitre présente en détails les échantillons étudiés ainsi que le dispositif expérimental utilisé lors des mesures. Enfin les chapitres 3 à 6 détaillent les expériences menées et les résultats obtenus ; le lecteur y trouvera des mesures de photoluminescence apportant la démonstration expérimentale des règles de sélection optique, l’identification des différents raies spectrales d’émission pour les différentstypes d’échantillons mentionnés plus haut ainsi que des mesures de photoluminescence résolues en temps permettant d’extraire la dynamique des propriétés des porteurs photo-générés. Une part importante de ce manuscrit est consacrée à l’étude expérimentale des propriétés excitoniques de ces matériaux dont la structure de bande électronique est finalement sondée via des études de magnéto-spectroscopieThe possibility of isolating transition metal dichalcogenide monolayers by simple experimental means has been demonstrated in 2005, by the same technique used for graphene. This has sparked extremely diverse and active research by material scientists, physicists and chemists on these perfectly two-dimensional (2D) materials. Their physical properties inmonolayer formare appealing both fromthe point of view of fundamental science and for potential applications. Transition metal dichalcogenidemonolayers such asMoS2 have a direct optical bandgap in the visible and show strong absorption of the order of 10% per monolayer. For transistors based on single atomic layers, the presence of a gap allows to obtain high on/off ratios.In addition to potential applications in electronics and opto-electronics these 2D materials allow manipulating a new degree of freedom of electrons, in addition to the spin and the charge : Inversion symmetry breaking in addition to the strong spin-orbit coupling result in very original optical selection rules. The direct bandgap is situated at two non-equivalent valleys in k-space, K+ and K−. Using a specific laser polarization, carriers can be initialized either in the K+ or K− valley, allowing manipulating the valley index of the electronic states. This opens up an emerging research field termed "valleytronics". The present manuscript contains a set of experiments allowing understanding and characterizing the optoelectronic properties of these new materials. The first chapter is dedicated to the presentation of the scientific context. The original optical and electronic properties of monolayer transition metal dichalcogenides are demonstrated using a simple theoreticalmodel. The second chapter presents details of the samples and the experimental setup. Chapters 3 to 6 present details of the experiments carried out and the results obtained. We verify experimentally the optical selection rules. We identify the different emission peaks in the monolayer materials MoS2, WSe2 and MoSe2. In time resolved photoluminescence measurements we study the dynamics of photo-generated carriersand their polarization. An important part of this study is dedicated to experimental investigations of the properties of excitons, Coulomb bound electron-hole pairs. In the final experimental chapter, magneto-Photoluminescence allows us to probe the electronic band structure and to lift the valley degeneracy
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Sayed-Ahmad, Baraza Yuman. "Theoretical and experimental studies of structure and functionalization of 2D nanomaterials." Thesis, Nantes, 2019. http://www.theses.fr/2019NANT4016/document.
Повний текст джерелаАнотація:
Dans cette thèse, des matériaux 2D ont été étudiés principalement par méthodes ab initio de type DFT, ainsi que par des techniques expérimentales. Le manuscrit se focalise sur le polymorphisme, les bords et la fonctionnalisation du matériau 2D MoS2. Nous montrons que la fonctionnalisation avec des espèces similaires peut être étendue à d’autres matériaux 2D en incluant des études sur le graphène. Nous étudions par des calculs DFT la stabilité relative des polymorphes et des reconstructions des bords de monocouches de MoS2, et nous proposons des modèles qualitatifs pour comprendre la stabilité. La fonctionnalisation du MoS2 par des stratégies covalentes et non covalentes a également été étudiée en lien avec des expérimentateurs. En particulier, nos calculs indiquent que le MoS2 peut être fonctionnalisé de manière covalente avec des dérivés de 1,2- dithiolane. Cette fonctionnalisation se fait préférentiellement sur les bords, produisant un hybride stable. Ceci peut être utilisé pour produire un système avec un groupe pyrène photoactif qui interagit de manière significative avec MoS2. Les résultats expérimentaux obtenus par nos collaborateurs sont conformes à nos résultats théoriques et une interaction entre le fragment pyrène photoexcité et MoS2 a été mise en évidence. La fonctionnalisation directe non covalente de la surface de MoS2 avec du pyrène a également été étudiée théoriquement et expérimentalement, en trouvant une interaction similaire à celle du cas précédent. Finalement, nous montrons que des dérivés de pyrène peuvent être utilisés pour la fonctionnalisation de matériaux liés au graphène, système d’intérêt pour le stockage de l'énergieIn this thesis, ab initio DFT methods and complementary experimental techniques are used to study 2D materials. The manuscript focuses on our studies on the polymorphism, edges and functionalization of the 2D-material MoS2. Additionally, we show that functionalization with similar species can be extended to other 2D materials by including studies on the functionalization of graphene. We have studied using DFT calculations the relative stability of different MoS2 polymorphs and associated edge reconstructions, and have proposed qualitative models for understanding the stability trends. Functionalization of MoS2 by covalent and non-covalent strategies is also explored in collaboration with experimental partners. In particular, our calculations indicate that MoS2 can be covalently functionalized, preferentially at edges, leading to a final stable hybrid. This strategy is used to functionalize MoS2 with a photoactive pyrene group that shows significant interaction with MoS2. Experimental results obtained by our collaborators are consistent with our theoretical findings, and an interaction between the photoexcited pyrene moiety and MoS2 is found. A similar interaction is found for direct noncovalent functionalization of the basal plane of MoS2 both theoretically and experimentally. Finally, we show that pyrene derivatives can also be used for functionalizing graphenerelated materials for energy storage applications
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Mrzel, A., A. Kovic, A. Jesih, and M. Vilfan. "Decoration of MoSI Nanowires with Platinum Nanoparticles and Transformation into Molybdenum-nanowire Nased Networks." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35168.
Повний текст джерелаАнотація:
In this communication, we present solution-based coating procedure of MoSI nanowires (NW) with
platinum nanoparticles. The average particle diameter was found to be around 2.82 nm, showing a narrow
size distribution. This single-step in situ reduction method at room temperature in water solution can
easily be applied for large-scale applications. We also prepared two-dimensional networks of MoSI NW
bundles by deposition via spraying from a purified stable dispersion in acetonitrile onto NaCl crystals and
nonconductive silicon wafer with pre-assembled molybdenum electrodes. The formation of a conductive
molybdenum network was achieved by annealing in hydrogen due to coalescence of the templates MoSI
bundles during transformation. Stable water dispersion of molybdenum NW network was prepared by
simply dissolving the NaCl substrate with molybdenum network on the surface.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35168
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James, Derak J. "Synthesis and photocatalytic activity of the MoS₂ and WS₂ nanoparticles in degradation of organic compounds." Muncie, Ind. : Ball State University, 2009. http://cardinalscholar.bsu.edu/653.
Повний текст джерелаКниги з теми "MoS2 Nanoparticles"
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Jolivet, Jean-Pierre. Metal Oxide Nanostructures Chemistry. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190928117.001.0001.
Повний текст джерелаАнотація:
This much-anticipated new edition of Jolivet's work builds on the edition published in 2000. It is entirely updated, restructured and increased in content. The book focuses on the formation by techniques of green chemistry of oxide nanoparticles having a technological interest. Jolivet introduces the most recent concepts and modelings such as dynamics of particle growth, ordered aggregation, ionic and electronic interfacial transfers. A general view of the metal hydroxides, oxy-hydroxides and oxides through the periodic table is given, highlighting the influence of the synthesis conditions on crystalline structure, size and morphology of nanoparticles. The formation of aluminum, iron, titanium, manganese and zirconium oxides are specifically studied. These nanomaterials have a special interest in many technological fields such as ceramic powders, catalysis and photocatalysis, colored pigments, polymers, cosmetics and also in some biological or environmental phenomena.
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Wohlbier, Thomas. Nanohybrids. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901076.
Повний текст джерелаАнотація:
The book covers preparation, designing and utilization of nanohybrid materials for biomedical applications. These materials can improve the effectiveness of drugs, promote high cell growth in new scaffolds, and lead to biodegradable surgical sutures. The use of hybrid magneto-plasmonic nanoparticles may lead to non-invasive therapies. The most promising materials are based on silica nanostructures, polymers, bioresorbable metals, liposomes, biopolymeric electrospun nanofibers, graphene, and gelatin. Much research focuses on the development of biomaterials for cell regeneration and wound healing applications.
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Burke, A., D. Carroll, Frank Torti, and S. V. Torti. Bifunctional nanomaterials for the imaging and treatment of cancer. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533060.013.13.
Повний текст джерелаАнотація:
This article examines the potential of bifunctional nanomaterials for the imaging and treatment of cancer. Several nanomaterials possess properties desirable for a cancer therapy and have been the subject of research as anticancer agents. Those that have received the most attention include encapsulated iron oxides, single- and multiwalled carbon nanotubes, gold nanorods and gold nanoshells. This article first considers thermal ablative therapy incancer, focusing on the mechanisms of thermotoxicity and thermoresistance before discussing a number of nanomaterials with applications for cancer treatment. In particular, it evaluates the use of nanomaterials in thermal therapy. It also looks at gold nanoshells and nanorods, taking into account their physical properties, and concludes with an assessment of iron-oxide nanoparticles and future directions for nanomaterials as multifunctional agents for cancer therapy.
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Benisty, Henri, Jean-Jacques Greffet, and Philippe Lalanne. Introduction to Nanophotonics. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780198786139.001.0001.
Повний текст джерелаАнотація:
The aim of this book is to cover the scope of Nanophotonics, a discipline that has emerged around the turn of the millennium. It results from the merge of different communities working in different aspects of light-matter interaction at the nanoscale. These include near-field optics and super-resolution microscopy, photonic crystals, diffractive optics, plasmonics, optoelectronics, synthesis of metallic and semiconductor nanoparticles, two-dimensional materials and metamaterials. Our feeling when we started the project was that a book covering most of these aspects altogether was lacking. The field is so rapidly evolving that it is impossible to summarize all the recent breakthroughs. The goal of this book is to provide a self-contained discussion of the fundamentals of the different subfields involved in nanophotonics. The current project is a collaborative project between three researchers that have been actively involved in the field from different communities. Henri Benisty has a background in semiconductor physics and optoelectronics, Jean-Jacques Greffet has a background in near-field optics and light scattering, Philippe Lalanne has a background in diffractive optics and photonic crystals. All of them made significant contributions to the advancement of the field. The book material is based on lectures that have been given by them at the Institut d’Optique Graduate School (Palaiseau, Bordeaux and Saint-Etienne).
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Van Dyk, Jacob. The Modern Technology of Radiation Oncology, Vol 4. Medical Physics Publishing, 2020. http://dx.doi.org/10.54947/9781951134020.
Повний текст джерелаАнотація:
High praise continues to come in for the 4th volume of Jake Van Dyk's The Modern Technology of Radiation Oncology. From Peter Metcalfe in Physical and Engineering Sciences in Medicine… "Thank goodness medical physics has Jacob Van Dyk. Like Tiger Woods and Phil Mickelson in golf, his textbooks continue to make major comebacks. He has managed to assemble the most talented among us to sustain the up-to-date knowledge that is essential to our profession. Reference knowledge from this textbook will help ensure the medical physics profession is at the cutting edge of cancer research and clinical treatment. This textbook has taken pride of place on my bookshelf, right next to my most treasured Porsche magazines. I could not give it a higher accolade than that." From Rajesh A. Kinhikar in Journal of Medical Physics…"This resourceful book has aimed to serve as a comprehensive textbook for the practicing radiotherapy professionals. I would like to congratulate the authors and the Editor for such a high?quality scientific feast and strongly recommend the fourth volume of The Modern Technology of Radiation Oncologyto the clinical medical physicists and radiation oncology professionals involved with the rapidly evolving radiotherapy." New topics addressed in volume 4 include surface-guided radiation therapy (RT), PET/MRI, real-time MRI guidance, robust optimization, automated treatment planning, artificial intelligence, adaptive RT, machine learning, big data, radiomics, particle therapy RBE, nanoparticle applications, economic considerations, global medical physics activities, global access to RT, and FLASH RT. The volumes in this series have not only been valued by medical physicists and radiation oncologists in clinical practice around the world, but have also provided an important learning resource for residency programs, radiation technologists, dosimetrists, research students, biomedical engineers, and ancillary professionals related with radiotherapy. Administrators and scientists affiliated with the practice of radiation therapy will also find this book a useful resource.
Частини книг з теми "MoS2 Nanoparticles"
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Arunkumar, N., P. Eashwar Siddharth, Aravind Parthiban, K. Dhanapal, A. Stephen, and N. E. Arun Kumar. "Effect of Sensitization on Electroless Nickel Plating of MoS2 Nanoparticles." In Lecture Notes on Multidisciplinary Industrial Engineering, 623–31. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9425-7_56.
Повний текст джерела
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Yadav, Sarita. "Enhancement in Optical Absorbance of ZnO Nanoparticles by Introducing MoS2 Nanosheets." In Springer Proceedings in Physics, 77–82. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2592-4_9.
Повний текст джерела
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Eidelman, O., H. Friedman, and R. Tenne. "Metallic Films with Fullerene-Like WS2 (MoS2) Nanoparticles: Self-Lubricating Coatings with Potential Applications." In NATO Science for Peace and Security Series A: Chemistry and Biology, 59–67. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-2488-4_6.
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Shreya, Peeyush Phogat, Ranjana Jha, and Sukhvir Singh. "Elevated Refractive Index of MoS2 Amorphous Nanoparticles with a Reduced Band Gap Applicable for Optoelectronics." In Lecture Notes in Mechanical Engineering, 431–39. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-2349-6_39.
Повний текст джерела
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Filipović, Nenad, Nina Tomić, Maja Kuzmanović, and Magdalena M. Stevanović. "Nanoparticles. Potential for Use to Prevent Infections." In Urinary Stents, 325–39. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04484-7_26.
Повний текст джерелаАнотація:
AbstractOne of the major issues related to medical devices and especially urinary stents are infections caused by different strains of bacteria and fungi, mainly in light of the recent rise in microbial resistance to existing antibiotics. Lately, it has been shown that nanomaterials could be superior alternatives to conventional antibiotics. Generally, nanoparticles are used for many applications in the biomedical field primarily due to the ability to adjust and control their physicochemical properties as well as their great reactivity due to the large surface-to-volume ratio. This has led to the formation of a new research field called nanomedicine which can be defined as the use of nanotechnology and nanomaterials in diagnostics, imaging, observing, prevention, control, and treatment of diseases. For example, coverings or coatings based on nanomaterials are now seen as a promising strategy for preventing or treating biofilms formation on healthcare kits, implants, and medical devices. Toxicity, inappropriate delivery, or degradation of conventionally used drugs for the treatment of infections may be avoided by using nanoparticles without or with encapsulated/immobilized active substances. Most of the materials which are used and examined for the preparation of the nanoparticles with encapsulated/immobilized active substances or smart reactive nanomaterials with antimicrobial effects are polymers, naturally derived antimicrobials, metal-based and non-metallic materials. This chapter provides an overview of the current state and future perspectives of the nanoparticle-based systems based on these materials for prevention, control, or elimination of biofilm-related infections on urinary stents. It also addresses manufacturing conditions indicating the huge potential for the improvement of existing and development of new promising stent solutions.
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Milán-Rois, Paula, Ciro Rodriguez-Diaz, Milagros Castellanos, and Álvaro Somoza. "Conjugation of Nucleic Acids and Drugs to Gold Nanoparticles." In Methods in Molecular Biology, 103–16. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2010-6_6.
Повний текст джерелаАнотація:
AbstractGold nanoparticles (AuNPs) can be used as carriers for biomolecules or drugs in cell culture and animal models. Particularly, AuNPs ease their internalization into the cell and prevent their degradation. In addition, engineered AuNPs can be employed as sensors of a variety of biomarkers, where the electronic and optical properties of the AuNPs are exploited for a convenient, easy, and fast read out. However, in all these applications, a key step requires the conjugation of the different molecules to the nanoparticles. The most common approach exploits the great affinity of sulfur for gold. Herein, we summarize the methods used by our group for the conjugation of different molecules with AuNPs. The procedure is easy and takes around 2 days, where the reagents are slowly added, following an incubation at room temperature to ensure the complete conjugation. Finally, the unbound material is removed by centrifugation.
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"Experimental Study of Lubricating Property at Grinding Wheel/Workpiece Interface Under NMQL Grinding." In Enhanced Heat Transfer Mechanism of Nanofluid MQL Cooling Grinding, 275–97. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1546-4.ch012.
Повний текст джерелаАнотація:
Nanofluid is the suspension formed by lubricating oil and nanoparticles with particles sizes of 1~100 nm, and common nanoparticles include metal nanoparticles (Cu, Ag, etc.), oxide nanoparticles (Al2O3, SiO2, ZrO2, etc.), carbides (CNT, diamond), and MoS2 nanoparticles, etc. Different nanoparticles exhibit various physicochemical properties (e.g., structure and shape), which can influence their tribological characteristics. In this work, six nanofluids, namely, MoS2, SiO2, diamond, carbon nanotubes (CNTs), Al2O3, and ZrO2, were used as minimum quantity lubrication grinding fluids to select the kind of nanoparticles with optimum lubrication performance in grinding nickel alloy GH4169. Experimental results concluded the following: 1) Nanoparticles with spherical or sphere-like molecular structure and nanofluids with high viscosity demonstrate superior lubrication performances. 2) The polishing effect of nanodiamond particles enhances their surface morphology. 3) The lubricating property of the six nanofluids is described in the following order: ZrO2 < CNTs < ND < MoS2 < SiO2 < Al2O3.
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"Optimization Design of Process Parameters for Different Workpiece Materials in NMQL Grinding With Different Vegetable Oils." In Enhanced Heat Transfer Mechanism of Nanofluid MQL Cooling Grinding, 337–57. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1546-4.ch015.
Повний текст джерелаАнотація:
This research shows with superior lubricating, heat-conducting properties, and proper market price, Al2O3 and MoS2 nanoparticles have broad application prospects as lubricant additives. This work has been researched, and most researches are restricted to using one kind of lubricants to machine specific workpiece or multiple workpieces. There has been no systematic and detailed analysis of grinding performances from cutting mechanisms and debris formation mechanisms of different workpieces. Therefore, analysis of signal to noise ratio(S/N), variance, microstructure, and morphology analysis were used to study the influence of different typical nanofluid lubricants on the grinding performance of different materials in this chapter. Results showed that the optimal grinding parameters are using nodular cast iron and MoS2 nanofluid. Compared with other lubricants, MoS2 nanofluid can exert a significant effect on reducing wear of grinding wheel. In order to reduce surface roughness, MQL lubricating oils of the following sequence can be used: Al2O3 nanofluid, MoS2 nanofluid, and pure palm oil.
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Li, Changhe, and Hafiz Muhammad Ali. "Experimental Research on Minimum Quantity Lubrication Surface Grinding With Different Cooling and Lubrication Conditions." In Research Anthology on Synthesis, Characterization, and Applications of Nanomaterials, 1052–79. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-8591-7.ch043.
Повний текст джерелаАнотація:
Given the increasing attention to environmental and health problems caused by machining, the development of an environmentally friendly grinding fluid has become an urgent task. The cooling and lubricating properties of different cooling and lubricating conditions were analyzed. The influence mechanism of nanofluids minimum quantity lubrication (NMQL) on cooling and lubricating effect was revealed with different nanoparticles (MoS2, CNT, ZrO2) and different volume concentrations of MoS2 nanofluids (1%, 2%, 3%). The experimental results showed that the temperature rise (258 °C) and grinding force (Fn=70 N, Ft=27 N) obtained under NMQL grinding were the closest to the flood grinding. The specific grinding energy of MoS2 nanofluids was the lowest, which was 47 J/mm3. When the volume concentration was 2%, the best cooling and lubricating effect was obtained. The surface roughness of the workpiece was the lowest (Ra = 0.283 μm; Rz = 0.424 μm).
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"Experimental Research on Minimum Quantity Lubrication Surface Grinding With Different Cooling and Lubrication Conditions." In Enhanced Heat Transfer Mechanism of Nanofluid MQL Cooling Grinding, 132–59. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1546-4.ch006.
Повний текст джерелаАнотація:
Given the increasing attention to environmental and health problems caused by machining, the development of an environmentally friendly grinding fluid has become an urgent task. The cooling and lubricating properties of different cooling and lubricating conditions were analyzed. The influence mechanism of nanofluids minimum quantity lubrication (NMQL) on cooling and lubricating effect was revealed with different nanoparticles (MoS2, CNT, ZrO2) and different volume concentrations of MoS2 nanofluids (1%, 2%, 3%). The experimental results showed that the temperature rise (258 °C) and grinding force (Fn=70 N, Ft=27 N) obtained under NMQL grinding were the closest to the flood grinding. The specific grinding energy of MoS2 nanofluids was the lowest, which was 47 J/mm3. When the volume concentration was 2%, the best cooling and lubricating effect was obtained. The surface roughness of the workpiece was the lowest (Ra = 0.283 μm; Rz = 0.424 μm).
Тези доповідей конференцій з теми "MoS2 Nanoparticles"
1
Ren, W. P., Q. H. Tan, Q. J. Wang, and Y. K. Liu. "Decoration of Au Nanoparticles on Monolayer MoS2 Transistor." In 2019 IEEE 2nd International Conference on Electronics Technology (ICET). IEEE, 2019. http://dx.doi.org/10.1109/eltech.2019.8839456.
Повний текст джерела
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Ghosh, Sourav, Uday Pratap Azad, and Ashish Kumar Singh. "Synthesis of colloidal MoSx nanoparticles and their transformation into carbon supported MoS2 nanocomposite." In ADVANCES IN BASIC SCIENCE (ICABS 2019). AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5122574.
Повний текст джерела
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Shutov, Anton D., Zhenhuan Yi, Jizhou Wang, Alexander M. Sinyukov, Zhe He, Chenwei Tang, Jiahao Chen, et al. "Coherent Anti-Stokes Raman Scattering Enhanced by MoS2 Nanoparticles." In Frontiers in Optics. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/fio.2018.jw3a.40.
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Li Bin, Yang Daheng, Chen Jiuju, Yang Xiaolei, and Meng Qinggang. "Sonochemical preparation and characterization of MoO3 and MoS2 nanoparticles." In 2011 International Conference on Management Science and Industrial Engineering (MSIE). IEEE, 2011. http://dx.doi.org/10.1109/msie.2011.5707604.
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Rapoport, L., N. Fleischer, and R. Tenne. "Tribological Applications of WS2 (MOS2) Inorganic Fullerene-Like Nanoparticles as Solid Lubrication." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63173.
Повний текст джерелаАнотація:
Fullerene-like WS2 (MoS2) nanoparticles (IF) have been studied in the past [1–3] Their efficacy as additives for lubrication fluids has been demonstrated. [4–5] Recently, IF-WS2 nanoparticles were confined inside a porous and densified bronze-graphite matrix, prepared by powder metallurgy (PM) technique. Substantial reduction in both friction and wear, and an increase in the critical load were observed [6]. New applications of IF nanopartcles as development of polymer nanocomposites, burnishing and friction of ceramic materials under severe contact conditions are presented in this work.
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Pal, Arnab, Tushar K. Jana, and Kuntal Chatterjee. "MoS2 embedded TiO2 nanoparticles for concurrent role of adsorption and photocatalysis." In DAE SOLID STATE PHYSICS SYMPOSIUM 2017. Author(s), 2018. http://dx.doi.org/10.1063/1.5028769.
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Eilenberger, Falk, Franz J. F. Lochner, Stefan Fasold, Antony George, Paul D. Harrison, Tobias Bucher, Christoph Menzel, et al. "Enhancement of light-matter interaction in MoS2 monolayers by resonant nanoparticles." In 2016 Progress in Electromagnetic Research Symposium (PIERS). IEEE, 2016. http://dx.doi.org/10.1109/piers.2016.7735455.
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Hu, K. H., J. Wang, S. Schraube, Y. F. Xu, X. G. Hu, and R. Stengler. "Tribological Behavior of Self-Lubrication Bearing Materials of Steel-Copper-Polyoxymethylene Containing MoS2-IC Nanoparticles." In ASME/STLE 2007 International Joint Tribology Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ijtc2007-44132.
Повний текст джерелаАнотація:
Intercalation compound of polyoxymethylene into molybdenum disulfide nanoparticles (POM/MoS2-IC) were prepared from trioxane, dioxolane and restacked exfoliated-MoS2. The so prepared nanocomposite was used as the plastic layer of self-lubrication bearing materials of steel-copper-POM. Pure POM was also selected as a comparative sample. Tribological behaviors of the obtained samples were studied on an end-face tribometer. Wear scar surfaces of the two plastic layers were characterized by a field emission scanning electron microscope. The elements of the counterpart steel surface were investigated by X-ray photoelectron spectroscopy. Results showed the wear surface of steel-copper-pure polyoxymethylene consisted of deep furrows, large-area scars and obvious flow marks. However, self-lubrication bearing materials of steel-copper-polyoxymethylene containing MoS2-IC nanoparticles presented excellent friction reduction and wear resistance especially under high loads. POM/MoS2-IC nanoparticles and its tribochemical resultants restrained the plowing effect of the counterpart steel on the plastic layer through forming a transferred film on the counterpart friction surface.
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Pal, Arnab, Shubhamita Dutta, Tushar K. Jana, and Kuntal Chatterjee. "Electrocatalytic hydrogen evolution study of MoS2 with different loading of TiO2 nanoparticles." In DAE SOLID STATE PHYSICS SYMPOSIUM 2018. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5113004.
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Parangusan, Hemalatha, Jolly Bhadra, Razen Al-Qudah, Hibballa Elgurashi, Marwa Abdelhakem, and Ebtihal Mohaned. "Liquid exfoliated MoS2 Sheet coupled with Conductive Polyaniline for Gas Sensor." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0012.
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Polyaniline (PANI)/MoS2 composites with porous microspheres were prepared by a hydrothermal and in situ polymerization method. The structural, optical, and morphological properties were characterized by X-ray powder diffraction, FTIR, scanning electron microscope, transmission electron microscope. The XRD results confirmed that the PANI/MoS2 composite was formed. Morphological characterization reveals that the successful formation of few to multilayered MoS2 nanosheet intercalated with the PANI nanoparticles.
Звіти організацій з теми "MoS2 Nanoparticles"
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Venedicto, Melissa, and Cheng-Yu Lai. Facilitated Release of Doxorubicin from Biodegradable Mesoporous Silica Nanoparticles. Florida International University, October 2021. http://dx.doi.org/10.25148/mmeurs.009774.
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Cervical cancer is one of the most common causes of cancer death for women in the United States. The current treatment with chemotherapy drugs has significant side effects and may cause harm to healthy cells rather than cancer cells. In order to combat the potential side effects, nanoparticles composed of mesoporous silica were created to house the chemotherapy drug doxorubicin (DOX). The silica network contains the drug, and a pH study was conducted to determine the conditions for the nanoparticle to disperse the drug. The introduction of disulfide bonds within the nanoparticle created a framework to efficiently release 97% of DOX in acidic environments and 40% release in neutral environments. The denotation of acidic versus neutral environments was important as cancer cells are typically acidic. The chemistry was proved with the incubation of the loaded nanoparticle into HeLa cells for a cytotoxicity report and confocal imaging. The use of the framework for the anticancer drug was shown to be effective for the killing of cancerous cells.
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Choudhary, Ruplal, Victor Rodov, Punit Kohli, John D. Haddock, and Samir Droby. Antimicrobial and antioxidant functionalized nanoparticles for enhancing food safety and quality: proof of concept. United States Department of Agriculture, September 2012. http://dx.doi.org/10.32747/2012.7597912.bard.
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General concept. The reported 1-year study tested the feasibility ofpreparing antimicrobial and antioxidant nanoparticlesfunctionalized with natural phenolic compounds, as a first step to reach the ultimate goal - improving safely and quality of foods by developing novel antimicrobial and antioxidant food-contacting materials. The secondary objectives of the study were (a) selecting the most promising phenoliccompounds, (b) building nanoparticles with the selected phenolicgrafted on their Surface, and (c) testing antimicrobial and antioxidant properties of these particles. The study was expected to provide a " go/no go" decision as concerning the prospects of phenolic- bound nanoparticles as antimicrobial and antioxidant agents. Results. In course of the feasibility study, curucminwas chosen as the most promising phenoliccompound due to its high antibacterial activity exceeding other tested compounds by at leas one order of magnitude. Lipsome-typephospholipid/polydiacetylene(PDA) nanoparticlesfunctionalizedwith curcuminwere successfully built. The pitfall of limited curcumin amount that could be covalently bound to theparticle surface was circumvented by inclusion of curcunun in the liposome body. It was suggested onthe basis of fluorescence spectroscopy that curcuminwas bound by hydrophobic forces in the bi1ayer periphery of the Liposomesand therefore mightexert a contact effect on microorganisms. The curcumin functionalizednanoparticles(CFN) were shown to have a strong bactericidal activity towards both Gram-negative (E. coli) and Gram-positive (B. ce,·e11s) bacteria, but only limited effect against yeast. Furthermore, beyond the originallyplanned objectives, preliminary trials showed that CFN could be bound to silanized glass surface rendering aנבtiנnicrobial activity to the glass. Tnaddition, the particles showed antioxidantcapacity. Tberefore, it ,vas co11cluded tlוattlוeaims of tlוefeasibility study bad been successfully reached an
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Choudhary, Ruplal, Victor Rodov, Punit Kohli, Elena Poverenov, John Haddock, and Moshe Shemesh. Antimicrobial functionalized nanoparticles for enhancing food safety and quality. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598156.bard.
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Original objectives The general goal of the project was to utilize the bactericidal potential of curcumin- functionalizednanostructures (CFN) for reinforcement of food safety by developing active antimicrobial food-contact surfaces. In order to reach the goal, the following secondary tasks were pursued: (a) further enhancement of the CFN activity based on understanding their mode of action; (b) preparing efficient antimicrobial surfaces, investigating and optimizing their performance; (c) testing the efficacy of the antimicrobial surfaces in real food trials. Background to the topic The project dealt with reducing microbial food spoilage and safety hazards. Cross-contamination through food-contact surfaces is one of the major safety concerns, aggravated by bacterial biofilm formation. The project implemented nanotech methods to develop novel antimicrobial food-contact materials based on natural compounds. Food-grade phenylpropanoidcurcumin was chosen as the most promising active principle for this research. Major conclusions, solutions, achievements In agreement with the original plan, the following research tasks were performed. Optimization of particles structure and composition. Three types of curcumin-functionalizednanostructures were developed and tested: liposome-type polydiacetylenenanovesicles, surface- stabilized nanoparticles and methyl-β-cyclodextrin inclusion complexes (MBCD). The three types had similar minimal inhibitory concentration but different mode of action. Nanovesicles and inclusion complexes were bactericidal while the nanoparticlesbacteriostatic. The difference might be due to different paths of curcumin penetration into bacterial cell. Enhancing the antimicrobial efficacy of CFN by photosensitization. Light exposure strengthened the bactericidal efficacy of curcumin-MBCD inclusion complexes approximately three-fold and enhanced the bacterial death on curcumin-coated plastic surfaces. Investigating the mode of action of CFN. Toxicoproteomic study revealed oxidative stress in curcumin-treated cells of E. coli. In the dark, this effect was alleviated by cellular adaptive responses. Under light, the enhanced ROS burst overrode the cellular adaptive mechanisms, disrupted the iron metabolism and synthesis of Fe-S clusters, eventually leading to cell death. Developing industrially-feasible methods of binding CFN to food-contact surfaces. CFN binding methods were developed for various substrates: covalent binding (binding nanovesicles to glass, plastic and metal), sonochemical impregnation (binding nanoparticles to plastics) and electrostatic layer-by-layer coating (binding inclusion complexes to glass and plastics). Investigating the performance of CFN-coated surfaces. Flexible and rigid plastic materials and glass coated with CFN demonstrated bactericidal activity towards Gram-negative (E. coli) and Gram-positive (Bac. cereus) bacteria. In addition, CFN-impregnated plastic material inhibited bacterial attachment and biofilm development. Testing the efficacy of CFN in food preservation trials. Efficient cold pasteurization of tender coconut water inoculated with E. coli and Listeriamonocytogeneswas performed by circulation through a column filled with CFN-coated glass beads. Combination of curcumin coating with blue light prevented bacterial cross contamination of fresh-cut melons through plastic surfaces contaminated with E. coli or Bac. licheniformis. Furthermore, coating of strawberries with CFN reduced fruit spoilage during simulated transportation extending the shelf life by 2-3 days. Implications, both scientific and agricultural BARD Report - Project4680 Page 2 of 17 Antimicrobial food-contact nanomaterials based on natural active principles will preserve food quality and ensure safety. Understanding mode of antimicrobial action of curcumin will allow enhancing its dark efficacy, e.g. by targeting the microbial cellular adaptation mechanisms.
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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova, and Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
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The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.